Depletion and fractionation of nitrogen in collapsing cores

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Table A.1

Isotopic ratios of nitrogen-bearing species measured toward low-mass star-forming regions.

Species	Value	Source	Reference	Notes
Indirect measurements
HCN	200 ± 40	IRAS 16293A	Wampfler et al. (2014)	(1)
HCN	315 ± 45	OMC-3	Wampfler et al. (2014)	(2)
HCN	195 ± 55	L183	Hily-Blant et al. (2013a)
HCN	250 ± 110	L1544	Hily-Blant et al. (2013a)
HCN	150 ± 50	L1521E	Ikeda et al. (2002)
HCN	250 ± 80	L1527	Yoshida et al. (2019)
HNC	300 ± 100	L1527	Yoshida et al. (2019)
HC₃N	257 ± 54	TMC1(CP)	Taniguchi & Saito (2017)
HC₅N	344 ± 80	TMC1(CP)	Taniguchi & Saito (2017)
HC₅N	338 ± 12	L1527	Araki et al. (2016)	(1)
CN	510 ± 70	L1544	Hily-Blant et al. (2013a)
CN	476 ± 70	L1498	Hily-Blant et al. (2013a)

Direct measurements
N₂H⁺/N¹⁵NH⁺		L1544	Bizzocchi et al. (2013); Redaelli et al. (2018)	(3)

N₂H⁺/N¹⁵NH⁺		L183	Redaelli et al. (2018)	(3)

N₂H⁺/N¹⁵NH⁺	730 ± 250	L429	Redaelli et al. (2018)	(3)

N₂H⁺/N¹⁵NH⁺		L694-2	Redaelli et al. (2018)	(3)

N₂H⁺/N¹⁵NH⁺		I16293E	Daniel et al. (2016)	(3)

N₂H⁺/N¹⁵NH⁺	400	Barnard 1b	Daniel et al. (2013)	(3)

N₂H⁺/N¹⁵NH⁺	240 ± 50	OMC2-FIR4	Kahane et al. (2018)	(2, 6)

N₂H⁺/¹⁵NNH⁺		L1544	Bizzocchi et al. (2013); Redaelli et al. (2018)

N₂H⁺/¹⁵NNH⁺		L694-2	Redaelli et al. (2018), Crapsi et al. (2005)	(3)

N₂H⁺/¹⁵NNH⁺	320 ± 60	OMC2-FIR4	Kahane et al. (2018)	(2, 6)

NH₃	334 ± 50	Barnard 1b	Lis et al. (2010)

NH₃		Barnard 1b	Daniel et al. (2013)	(3)

NH₂D		Barnard 1b	Daniel et al. (2016)	(4)

NH₂D		L134N(S)	Gerin et al. (2009)	(5)

NH₂D		NGC 133-DCO+	Gerin et al. (2009)	(5)

NH₂D		L1689N	Gerin et al. (2009)	(5)

HCN	338 ± 28	L1498	Magalhães et al. (2018)	(3)

HC₃ N	400 ± 40	L1544	Hily-Blant et al. (2018b)	(3)

HC₃ N	270 ± 57	TMC1(CP)	Taniguchi & Saito (2017)

HC₃ N	275 ± 65	OMC2-FIR4	Kahane et al. (2018)	(2, 6)

HC₅ N	323 ± 80	TMC1(CP)	Taniguchi & Saito (2017)

CN		Barnard 1b	Daniel et al. (2013)	(3)

CN	270 ± 60	OMC2-FIR4	Kahane et al. (2018)	(2, 6)

CN	230 ± 80	L1527	Yoshida et al. (2019)	(1,7)

CN	310 ± 50	L1498	This work (see Appendix A.2)	(3)

Notes. The ratios have been separated into direct and indirect measurements, with the latter using the double-isotope-ratio method (see also Fig. 1). Also given are the references used for the density (see Fig. 4) when different from that for the isotopic ratio. (1) Low-mass Class 0. (2) Intermediate-mass Class 0. (3) Non-LTE calculation. (4) Replaces Gerin et al. (2009) and Daniel et al. (2013). (5) The LTE assumption introduces some bias on the ratio, essentially from the ¹⁵N isotopolog column density which may be overestimated (see Daniel et al. 2016, and Sect. 4.2.3). (6) An average density cm ⁻³ was computed based on the power-law from Crimier et al. (2009), with r₁ = 100 au and r₂ = 10⁴ au or 25′′ at 400 pc. (7) Same as (6) but with the power-law density profile from Shirley et al. (2002), with r₁ = 1000 au and r₂ = 2100 au or 15′′ at 140 pc. Assuming an abundance of 10% for Helium, the average density is ⟨n_H ⟩ = 6.5 × 10⁵ cm ⁻³.

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